Substrate processing apparatus, substrate processing method and storage medium

1. A substrate processing apparatus for performing a predetermined substrate process on a plurality of target substrates under a vacuum atmosphere, comprising: a plurality of processing parts installed within a single chamber and configured to perform the substrate process on the plurality of target substrates, respectively, each of the plurality of processing parts including a substrate mounting table on which one of the plurality of target substrates is mounted, a showerhead facing the substrate mounting table, and a cylindrical inner wall surrounding the substrate mounting table and the showerhead so as to define a process space located between the substrate mounting table and the showerhead; a gas supply mechanism positioned outside the single chamber and configured to separately supply a processing gas and a pressure control gas to the plurality of processing parts, the gas supply mechanism including a processing gas supply pipe and a pressure control gas supply pipe which are connected to the showerhead of each of the plurality of processing parts, and each of the processing gas supply pipe and the pressure control gas supply pipe including flow rate controllers and on-off valves; a single exhaust mechanism configured to collectively exhaust the processing gas and the pressure control gas within the plurality of processing parts, the single exhaust mechanism including an exhaust pipe connecting an exhaust port formed in a bottom portion of the single chamber with a vacuum pump via an automatic pressure control valve; and a control part as a process controller configured to control the gas supply mechanism and the single exhaust mechanism, wherein the control part performs a control to: while the inside of the plurality of processing parts are collectively exhausted by the single exhaust mechanism, supply the pressure control gas into the plurality of processing parts such that the internal pressure of the plurality of processing parts is stabilized to have the same level of pressure; when the internal pressure of the plurality of processing parts is stabilized to have the same level of pressure, start supply of the processing gas into the plurality of processing parts, and supply the pressure control gas into the plurality of processing parts at a first flow rate, such that the predetermined substrate process is performed in the plurality of processing parts, the processing gas and the pressure control gas being different from each other; and when the predetermined substrate process is terminated in at least one of the plurality of processing parts, stop the supply of the processing gas into the at least one of the plurality of processing parts, and supply the pressure control gas into the at least one of the plurality of processing parts at a second flow rate that is different from the first flow rate, while the processing gas continues to be supplied into the remaining of the plurality of processing parts and the pressure control gas continues to be supplied into the remaining of the plurality of processing parts at the first flow rate, wherein the first flow rate and the second flow rate are non-zero and set such that a difference in internal pressure among the plurality of processing parts is prevented from occurring due to the stop of the supply of the processing gas.

2. The substrate processing apparatus of claim 1 , wherein the control part is further configured to execute a first mode in which the single exhaust mechanism is controlled to collectively exhaust the processing gas within the plurality of processing parts and the flow rate controllers and the on-off valves are controlled separately such that a first gas as the processing gas is supplied to all the plurality of processing parts under the same gas supply condition, and a second mode in which the single exhaust mechanism is controlled to collectively exhaust the processing gas within the plurality of processing parts and the flow rate controllers and the on-off valves are controlled separately such that the first gas is supplied into some of the plurality of processing parts and a second gas as the processing gas is supplied into the other of the plurality of processing parts, the second gas being difference from the first gas, and in the second mode, the control part is further configured to separately control the flow rate controllers and the on-off valves of the gas supply mechanism to prevent the difference between the internal pressures of the plurality of processing parts.

3. The substrate processing apparatus of claim 2 , wherein, in the second mode, the control part is further configured to separately control the flow rate controllers and the on-off valves of the gas supply mechanism to control a flow rate of the second gas which is supplied into the other of the plurality of processing parts to such a level that the difference between the internal pressures of the plurality of processing parts is prevented.

4. The substrate processing apparatus of claim 2 , wherein the second gas includes at least one of an inert gas and a non-reactive gas which does not react with the target substrate.

5. The substrate processing apparatus of claim 4 , wherein, in the second mode, the control part is further configured to separately control the flow rate controllers and the on-off valves of the gas supply mechanism to: continuously supply the first gas into the some of the plurality of processing parts such that the target substrate in the some of the plurality of processing parts continue to be subjected to the substrate process, and stop the supply of the first gas into the target substrate in the other of the plurality of processing parts to terminate the substrate process, and supply the pressure control gas into the other of the plurality of processing parts, wherein the second gas is further used as the pressure control gas.

6. The substrate processing apparatus of claim 5 , wherein, prior to the substrate process, the control part is further configured to execute a pressure stabilization step of supplying the pressure control gas into the plurality of processing parts to stabilize the internal pressures of the plurality of processing parts by separately controlling the flow rate controllers and the on-off valves of the gas supply mechanism, in the pressure stabilization step, the control part is further configured to control the flow rate of the pressure control gas by separately controlling the flow rate controllers and the on-off valves of the gas supply mechanism such that the pressure control gas flows toward the single exhaust mechanism, the pressure control gas serving to prevent a backward flow of the first gas and the second gas between the plurality of processing parts in the second mode.

7. The substrate processing apparatus of claim 6 , wherein the pressure control gas is supplied into the plurality of processing parts in the substrate process, and wherein the flow rate of the pressure control gas in the pressure stabilization step is set to be higher than a flow rate of the pressure control gas in the substrate process.

8. The substrate processing apparatus of claim 7 , wherein the flow rate of the pressure control gas in the pressure stabilization step is set to be three times or more of those of some of the gases in the substrate process.

9. The substrate processing apparatus of claim 4 , wherein the second gas includes a gas used in diluting the first gas.

10. The substrate processing apparatus of claim 1 , wherein the single exhaust mechanism is shared by the plurality of processing parts installed within the single chamber.